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Prometheus Lights Alpha Series XM18-B Review (XM-L T5 4C | 1x18650)

Please do not hit the refresh button on your browser... this is indeed a review of Prometheus Lights' Alpha XM18-B and yes, that is indeed a picture of a bowl of noodles.
Specifically, it is a bowl of spicy Shin Ramyun (one of my favorites). Ramyun (or ramen [Japanese] / gong zai mian [Chinese]) is the proverbial fast food delight of many Asian cultures that really couldn't be simpler or quicker to make, thus living up to its "Instant Noodles" billing. Never mind that it provides you with nearly the entire recommended daily intake for sodium in one serving (most packages have about 1800mg), it is a delectable foundation with which you can build the perfect meal upon by garnishing it with eggs, vegetables, meat or seafood and supplementing it with side dishes. These will only serve to complement the unpronounceable exotic "ingredients", with disodium guanylate, disodium inosinate, disodium succinate just to name a few.

With that said, there are subtle but important steps involved in making just the right bowl of ramyun which my wife's hal muh nee (grandmother in Korean) had perfected. If you add too much water then you dilute the soup base and it comes out tasting bland (my tastebuds cry out for every last bit of that disodium wathcamacallit ingredient); overcook it and the noodles are mushy soft, likewise leaving it around for too long would allow the noodles to absorb too much water causing the same problem but with less soup. As age and health issues set in, it was one of the few meals she could easily whip up when we visited. Despite our protests that she shouldnít bother and to get some rest, she insisted and would meticulously prepare each bowl as if it were for royalty; the soup was always just the right amount of saltiness; there'd be well beaten eggs that created just the right amount of "fluff" upon hitting the boiling water and had great texture and flavor due to the perfect blending of the yolk and egg white; and last but certainly not least, the noodles were ALWAYS al dente! Bottom line is that her attention to details is why we could just about taste the love she poured her heart into preparing this humble meal.

I've had countless other bowls of ramyun since she passed on but it's something I've not quite tasted againÖ

Jason Hui (designer, fabricator, strategist & founder of Prometheus Lights) on the other hand may not have the same zeal for making ramyun but what he does share is an attention to details and loves, in his own words ďÖto make ideas realĒ. Fortunately for us flashaholics, one of those ideas was a dive light which in turn led to variations of other lights and eventually birthed the Alpha prototypes. At that point he didnít have any CNC machines, just a manual lathe and mill. That changed just over a year ago when he found an awesome deal on a very old Haas CNC mill. It was born at the Haas factory in Socal, lived its life in New Jersey for about 20 years, and then came all the way back across the country. Jason basically said to himself, ďif you buy this machine you are in the flashlight business...Ē so here we are. This review will cover as much about one of his ideas turned to reality as well as the man behind it.Note: Ti clip & Ti zipper pull are optional accessories

Packaging costs money, and this gets passed on to you, the buyer. It also (likely) means that it won't fit into a small USPS flat rate box...so shipping will be more expensive.

Jason is debating use of premium packaging and until he sorts that out, for now, he ships his lights in a standard USPS flat rate box w/some paper material for cushioning. The items arrived as such:
He dubs the package he sent ďThe ApprenticeĒ, which includes (beyond the light):
- 1 x AW 2900 mAh battery (that comes in a nifty little carrier that can be used to carry a spare)
- 1 x XTAR MP1 charger
- 1 x maintenance package consisting of 2 x spare o-rings and a small bottle of Nano-oil (this is not normally mentioned as he likes to throw it in as a surprise for his customers but I was authorized to disclose this spoiler)
- a report card on which he personally records by hand the following information for each light:

The apprentice package is great for budding flashaholics who donít yet have a battery/charger and ensures they are able to enjoy immediate use of their light as well as doing basic maintenance in the long run.

[NEW 5/15: CONDENSED VIDEO SUMMARYIf you don't have time to read through all the details (although I highly suggest you do ^_^) you can watch this quick summary video (but doesn't go into the depth that this review provides):]

DESIGN / FEATURES

Originally Posted by archer6817j

I enjoy a good metaphorical name from time to time like the gladiator, super nova, or death star...but they are meaningless.

An alphanumeric nomenclature was utilized for Jasonís lights as he feels it allows easy identification as follows:
- the first two letters identifies the LED in use (XM = XM-L, MC = MC-E, etc)
- the next two numeric characters denotes the battery size/type (18650ís thus far but he now has a shorty)
- the final letter identifies the reflector or optic in use (B for Boom)

In the case of the XM18-B, it features an XM-L LED powered by one 18650-sized battery and utilizing a Boom reflector:

Originally Posted by archer6817j

Everyone anodizes, very few EN plate. I want to be different...

Electroless Nickel plating is a rather unique finish as far as flashlights are concerned and the XM18-B is the only one in my current collection to feature it. The EN plating process is auto-catalytic; that is, it adheres to the substrate itís applied to without the need/use of a power source (unlike anodizing). The advantages it offers over anodizing is that it allows for uniform application even over complex shapes/curves and is slightly harder. The disadvantages though are; itís heavier, will increase the OD (outer diamter) of the object being plated and fingerprints badly. EN plated surfaces are still electrically conductive thus doesnít require the removal around areas where itís not desired (e.g. tubing ends), however, this also means that the XM18-B cannot be locked out at all.

There are currently three finishes available for standard Alpha series lights. I received a Stone Wash finish which, as its namesakes implies, is like a smooth stone and encompasses the entire outer surface of the light with the exception of the seven circular grooves:
Subjectively, itís an attractive finish and in conjunction with the EN plating that is slightly warm in color*, lends a distinct character to the light. However, EN plating will not cover any machining marks which Jason intentionally leaves behind as he likes to "...retain some evidence of the process". I suppose though that being a one-man setup, economics come in to play as well as it would take additional time and added cost to buff out every single mark.

Each light features a UCL lens and upon first glance, I thought a lens wasnít installed. It truly is that clear and non-reflective albeit, I donít know if itís specific to this particular lens, the type of AR coating used or a combo of both in conjucntion with the boom reflector:

There are seven circular grooves that serve as the only aesthetic element on the body:

The tailcap features a recessed black rubber cover of which underneath lies a McClicky switch:

This allows for tailstanding without any issues:

Originally Posted by archer6817j

Ödesign for disassembly and repair.

This is a main principle that Jason follows with the build of his lights. A bit of time, thought and revisions went into the mounting of the driver. He finally ended up with an implementation that was both aesthetically pleasing and still allows easy removal by either him or if so inclined, his clients:

The notch allows one to stick a screwdriver in it to easily dismount the driver:

As a prime example of attention paid to details, Jason places a blob of solder on the spring tips which is further sanded down to prevent the sharp cut-off form scratching up the batteries:

Overall, it's a sleek minimalistic design that is more organic in nature and offers a nice break from the standard tactical/tacticool fare.

THROUGH A DIFFERENT LENS...
With very few exceptions, flashlights are designed to cater to the male-dominated market. Beyond the SureFire Isis, I'm not aware of a light that was purposely designed with the fairer sex in mind (and no, an existing light with bright colors doesn't count). While I can't say it was Jason's intent, I personally find that the Alpha series lights have a unisex appeal to them. My wife agrees as well and the XM18-B is one of the few lights that has caught her interest and elicited comments beyond the typical ďThatís nice dearÖĒ when asked for her opinion.

Case in point, it can look manly when clipped to the exterior of a Maxpedition Fatboy and boldly displayed (scratches and dings be damned!) or decidedly feminine nestled within a LV Artsy MM (especially when adorned with a trinket of choice):

My wife doesnít like to carry any large, heavy items so the shorty tube will be her preference for those times I insist she carry a light for ďjust in caseĒ purposes:
Besides, it's one of the few lights that she'll actually carry that would fit in her clutch.

While it hasnít become her EDC (she prefers AAA-clicky format), she has ďborrowedĒ it every so often and finds the neutral tint to be quite pleasing and useful when picking out her clothes in the wee hours of the morning without needing to hit the lights to disturb anyone.
As can be seen above (exposure locked between L/R pairs and on AWB), the floody profile of the beam and the tint in particular has enabled her to keep the XM18-B on low (vs. med for Mr. Elfin) and has been a boon in helping distinguishing between the many different shades of her jeans (I don't ask her why she has so many pairs, and she doesn't ask me why I have so many flashlights... peace reigns supreme! ).

I often see threads requesting suggestions on gifting a light for a female recipient so perhaps this is one to keep in mind if said recipient is as particular about her style preferences as my wife.

The XM18-B runs about mid-pack among the 1 x 18650 sized lights in my collection but fits well in my medium-sized hands:
The smooth finish means itíll be more likely than not to create problems with grip under wet conditions or when wearing certain gloves (especially those made from cloth). Also, given the switch is recessed, I needed to grip the light further towards the end so that my thumb can fully depress the switch.

While the Alpha series was initiated on a 1 x 18650 platform, late last year, Jason started producing ďshortyĒ bodies that can accommodate both 16340* (w/the included sleeve) and 18350 cells. He recently put up a limited run of five of which I snapped one up to include in this review.

*Given the current draw of 2.8A on High, one should only use IMR cells.

I donít yet have an IMR 18350 but grabbed an old UF one (that is actually 37.4mm long) for testing and found that this particular cell created an issue in that once the head was completely tightened, the light wouldnít turn on. Once I loosened the head about ľ turn then the light came on. I havenít isolated the issue yet but something to keep in mind in case you happen to have these cells.

I didnít encounter any such problems using an AW IMR 16340 (the only 16340 cell that should be used given the high current draw this light is capable of). With the sleeve in place, I wasnít able to induce any battery rattle regardless of how hard I shook the light.

An additional point Iíd like to highlight is that the size of the ID of the tailcap-end of the tube is smaller than the OD of the head-end thus one couldnít simply attach the shorty tube as an extension to render it 2 x 18500 capable.

FIT & FINISH

Originally Posted by archer6817j

One thing that sets my lights apart is attention to every possible detail.

Based on various correspondence with Jason, itís evident he sets a pretty high-bar for both himself as well as his creations and is often not easily satisfied until he tweaks something until it canít be tweaked anymore (Iíd recommend reading his blog for examples). His pride of craftsmanship is only tangible in how it translates into his customersí pride of ownership. If other Prometheus Light ownersí units are like the sample I received then they should likely be pretty proud since the XM18-B is one of the best lights Iíve tested quality-wise (and I have tested my fair share).

Iím hard-pressed to find anything to fault. Features that ostensibly are purely for aesthetics at first blush are in fact intentional;

- the blue o-ring offers a striking contrast that begs for attention. However, looks aside, this o-ring is fluorosilicone based and costs considerably more than standard silicone o-rings. It offers excellent extreme temperature/weather properties, compression set resistance, fuel oil resistance (thus used in aircraft fuel systems). It does however have poor abrasion resistance but no worse than standard silicone:

- geometry comes in to play with a strategically milled taper towards the end of the head:
This was by design to prevent direct pressure (with the light laying flat) from being applied to the threads that reside directly on the inner diameter opposite of the taper thus greatly minimizing the chances of incurring any damage to them:
(pics re-used w/permission)

- another engineering decision applied to the head is that it is milled as a single piece with a solid band of material right aft of the reflector that greatly aids in both structural strength and heat dissipation:(pic re-used w/permission)

- the level of details is no less on the tail end, again with geometry invoked (vis-ŗ-vis the absence of uneven shapes) coupled with the raw strength of the material to help prevent crushing:

- the point where the tailclip meets the body with either tube falls on a raised surface and not a groove

The EN plating offers pretty effective natural lubricity with a coefficient of friction of EN on EN at .45 unlubricated and .2 lubricated (lower is better - source: Wikipedia). With the Nano-oil applied to the threads, the best way to describe the twisting of the head would be that itís akin to rubbing two steel ball bearings or qigong balls together. Itís not quite as smooth as say anodizing on anodizing but subjectively has a satisfying feel that to me, conveys a precision fit.

With that all said, here are a few nitpicks I did manage to find:

I was able to induce some battery rattle with the AW IMR but ony by shaking really vigorously, however, this is really par for the course for newer lights given the ever growing 18650 battery cells (that are really no longer 18x65) and thus the need to accomodate the larger sized cells in this format

there is a very faint buzzing noise from the McClicky in low mode that becomes slightly more pronounced in medium mode; this is regardless of the tube or battery is in use

Iím able to induce a rattling noise with the McClicky switch when it is depressed (on) but apparently, this is inherent to all McClicky switches and not particular to Jasonís build (McClicky owners, please feel free to chime in)

the switch on my unit was actually installed pretty tight thus requiring the use of a plier to remove it

In specific regards to the finish, while the bulk of machining is done by CNC there is still a lot of manual hand work involved as such, there may be some minor cosmetic imperfections that Jason intentionally leaves behind as previously mentioned:
Again, if you are looking for a cosmetically perfect light then you may wish to pursue an alternative finish/coating or perhaps even a bespoke model.

UI

Originally Posted by archer6817j

My philosophy is that simple is better.

There are 3 modes (L Ė M Ė H) that can be accessed through the tailcap switch. Given itís a forward-clicky, momentary use is possible. The last used mode is memorized provided the light is left-on in that mode for at least 2.5 seconds (please see [forthcoming] video review for further explanation). This is also retained through battery changes as well. In-line w/his philosophy, there are no extraneous modes to cycle through.

MEASURED PERFORMANCEAs of May, Iíve revised the calibration for my PVC LMD as follows:
- To measure lights with claimed output < 400lms, Iíll set the Xeno G10v2 on Med mode (180lms), set Extech HD450 to 400 range and calibrate sensor for 170lms
- To measure lights with claimed output > 400lms, Iíll set the Xeno G10v2 on High mode, set Extech HD450 to 4K range and calibrate sensor for 465lms after the output settles down (approx. 3-5 mins)

[to come]

MEASURED TINT
[ to come - for now, please see "THROUGH A DIFFERENT LENS..." section for a few pics of tint comparo vs. cool white light]

100ft (30.5m) Campsite shot
For details of these shots as well as comparo vs. 23 other lights, check here.

Also, here is a mini video review I did while camping (best to check thread linked above in beach beamshot before viewing this to get a better understanding of the route taken as well as a layout of the campsite):
]

RUNTIME
The relevant battery stats are provided above each runtime graph along with:
- Voltage of the battery at the start and end of the test
- Current draw as taken right before the test
- Actual runtime using ANSI FL1 (first in HR and then in M so for the AW2900 read this as 1hr OR 62min)
- NEW (as of May 2012): Lumens measured on PVC LMD @ 30 seconds
- Also for High, captured the temperature: ambient, the head at start and the max it reached (fan was used for all bats)
Using the AW2900, I slighty topped the claimed runtime of 1hr on High. This light is driven hard and while it has good heat dissapation, care should still be taken when using it continuously on high mode.

I will post results of other modes when completed but going strictly by on paper calculations using the current draw measured with AW2900; 867mA for Med & 128mA on Low, the runtimes should be 3.3hrs & 22.6hrs respectively.

NEW 5/15: While I wait for my AW battery order to arrive, I've conducted runtime w/shorty tube using the following cells. I suspect my AW IMR 16340 is no longer good as it's gone through many deep cycles so will look to rerun that in the future but for now, here is what you can reasonably expect with these cells:]
NEW 5/16: The AW IMR 18350 arrived and I just wrapped up the runtime and was able to squeeze 16min out of it before the low voltage warning kicked in. As you can see, the light was able to draw nearly the max current and thus able to stay in nearly flat regulation with the highest output for the entire run as compared to the other two cells. However, with the increased current draw comes higher temperature and max achieved was 117.4F, definitely nor recommended to run this light unattended/uncooled for long stretches.]

INITIAL CONCLUSIONThe XM18-B is a solid piece of old-fashioned hand-crafted goodness and quality-wise, is one of the best lights Iíve had the privilege of testing. It has been well-thought out, well-executed and where possible continually improved upon.

An uncertainty remains with the durability of the EN plating. Itís my first experience with a light that features it and only time will tell how it holds up. There is also the matter that Prometheus Lights is still a relatively young and small company without the lengthy track record of some of the larger players in the industry. However, if the XM18-B is any indication of the level of quality and thoughtful engineering we can expect from Jasonís products then Iím optimistic that he should be around for a long while leaving his maker's mark on his creations.

turboBB-licious

outstanding build quality with attention to details evident

use of boom reflector creates very nice floody smooth beam free from discernable artifacts and without abrupt transition from hotspot to corona to spill

Oh! it's lovely looking ramyun.
Shin means spicy or 辛 (in Chinese). You sweat a lot when eating hot or spicy foods in general. I think you were eating Shin Ramyun in a sewat. It's one of my favorite ramyuns too.
It's spicy but delicious. If you add an egg in soup and stir to blend, it become less spicy. It was out of this world. (Sometimes I cook good ramyun. Believe or not.)

The light shows very nice & clean beam profile. Also well regulated and nice runtime. The electroless nickel plating seems very nice & unique. What a wonderful light!
Thanks a lot for your time & effort. Excellent review. Tim!

Thx! I've only had the light for a month but thus far have not noticed anything adverse occuring with the finish (same goes for the shorty tube). However, just to be sure I understand your question correctly, is there an example you can provide of what tarnishing would look like?

Also, are you asking because you've encountered an issue with yours or just out of curiosity?

I'm not sure if I had addressed it correctly, but the finish on my brushed Alpha seems to darken around areas it was handled the most. I even have a few areas that have my fingerprints imprinted. I know this is not surface contaminant as I used liquid dishwashing soap to clean it, and the tarnishing persisted.

Just yesterday I got a lil but brave and took a mild 3M scouring pad and gently brushed the light in the direction of the brushed pattern. This was done in a sink of soapy water full of suds. The tarnishing leaves off the surface and the light shines again to its warm nickel brilliance.

Does Nickel develop patina like Ti and Cu does? At least it's not rust like on Fe.

I'm not sure if I had addressed it correctly, but the finish on my brushed Alpha seems to darken around areas it was handled the most. I even have a few areas that have my fingerprints imprinted. I know this is not surface contaminant as I used liquid dishwashing soap to clean it, and the tarnishing persisted.

Just yesterday I got a lil but brave and took a mild 3M scouring pad and gently brushed the light in the direction of the brushed pattern. This was done in a sink of soapy water full of suds. The tarnishing leaves off the surface and the light shines again to its warm nickel brilliance.

Does Nickel develop patina like Ti and Cu does? At least it's not rust like on Fe.

Sent from my iPhone using Tapatalk, please pardon typos.

Hi all I won't interject in this thread much, but I wanted to answer the tarnish question. Yes, nickel will tarnish. Think of it like sterling silver or (as suggested) copper...but not nearly as active. I wouldn't recommend scouring on a polished or stone washed light, but any kind of metal or silver polish should take the tarnish right off. I use a product called NevrDull. Check out the copper light thread in the Dark Sucks subforum for some before and after shots with NevrDull. As you found, tarnish is just on the surface so you can freshen it up whenever you like Personally I like to let mine go au-natural.

Thanks for the reply. The tarnishing starts to grow on me as it gives the light some character. I think bead blasted finish & stone washed finish would tarnish slower, but I can understand now why people would love the patina on Ti and Cu. I love the light more now!

To Tim and mods, please forgive if this thread seems to steer away, but I think that the tarnishing issue I brought up might be of concern to prospective owners, or a heads up if they're looking for such feature.

I noticed the tarnish too, good to hear that this is normal and removable if you want a shiny light.
It seems only to tarnish where I touched it with my fingers. The parts that are covered by the head or the clip aren't tarnished or at least not not that much.

Pics of tarnished/'clean' parts. Blasted/Polished version of the Alpha.

I'm brand new to the world of internet forums and found the CPF forum by accident. Literally everything I've learned about led flashlights has come from reading CPF and corresponding with Mr. Archer. I can't thank him enough for giving me a crash course in led technology in general and custom flashlights in particular. Now after exchanging literally 50 emails, I am the proud owner of Alpha light #114. This is an exceptional light, and one worthy of consideration by anyone looking for an extremely high quality light at a good price. My thanks also to Turbobb for an excellent review.

I'm brand new to the world of internet forums and found the CPF forum by accident. Literally everything I've learned about led flashlights has come from reading CPF and corresponding with Mr. Archer. I can't thank him enough for giving me a crash course in led technology in general and custom flashlights in particular. Now after exchanging literally 50 emails, I am the proud owner of Alpha light #114. This is an exceptional light, and one worthy of consideration by anyone looking for an extremely high quality light at a good price. My thanks also to Turbobb for an excellent review.

Welcome to the forum! You'll find that this is a very friendly community.

And congrats on the new light! My Alpha is my favorite light by far. I've had it for over 6 months and I use it 9 out of 10 times that I need light. And Jason is the man!

@ Ore : Thanks for posting the nice pics. Can I use them on my site to illustrate the patina? However, I'm really posting to say that o-ring looks a little dry. Don't forget the nano oil! Fluorosilicone don't like friction Okay, zipping my lip back up!